> This is because there is no file descriptor or anything else associated> with the pages which permits the kernel to clean stuff up on unclean> application exit. Also there are the obvious issues with permitting> pinning of unbounded amounts of memory.

Then that might explain the "bug" that we're seeing with get_user_pages(). We've been assuming that get_user_pages() mappings are permanent.

Well, I was just about to re-implement get_user_pages() support in our driver to demonstrate the bug. I guess I'll hold off on that.

If you look at the Infiniband code that was recently submitted, I think you'll see it does exactly that: after calling mlock(), the driver calls get_user_pages(), and it stores the page mappings for future use.

-- Timur TabiStaff Software Engineertimur.tabi@ammasso.com

One thing a Southern boy will never say is,"I don't think duct tape will fix it." -- Ed Smylie, NASA engineer for Apollo 13-To unsubscribe from this list: send the line "unsubscribe linux-kernel" inthe body of a message to majordomo@vger.kernel.orgMore majordomo info at http://vger.kernel.org/majordomo-info.htmlPlease read the FAQ at http://www.tux.org/lkml/